CLEAR CREEK COUNTY, Colo. - Crews will be blasting rock at the Twin Tunnels near Idaho Springs on Tuesday.
Drivers are being warned to expect delays of one hour or more on Interstate 70 from 8:30 a.m. to 6 p.m.
CDOT officials said the blasting schedule for the Westbound Twin Tunnels project will be "aggressive and may cause heavy delays."
Crews are blasting into the rock to create room for a third lane for westbound I-70. However, CDOT is not yet actually adding a third westbound lane. The project is just creating the room for it.
"With resources still in place from the 2013 project that widened the eastbound tunnel, it is estimated that doing this work now will save $5 million to $7 million," CDOT said.
Eastbound I-70 was expanded last year and that third lane is open.